Do you have any tricks to fix them? I teach my students a few fixesand I notice that the fix actually allows them an opportunity to be creative.

Teaching adults for several years taught me to teach them once they were throwing decently to make that first big pull to really work out the bottom, and continue to do so until the pot cylinder was pulled. Practice makes this happen, but understanding the concept makes the practice work.

Im still a begginner by most professional standards, but I find my pots rarely have accidentally heavy bottoms; if I am careful, I trimmed the wieght. If I'm not (because I'm lazy) I leave the wieght alone. Two things have helped me reduce trimming - careful measurement of the bottom when I throw using a needle tool, before I pull the walls, and making sure that I remove buttresses (by indenting on base of the outside) when I start pulling up the walls. Both of my teachers in throwing have emphasized this second step, and when it is not done, I find it very difficult to pull the clay up into the body.

If I throw a heavy bottom, then I trim. I like footed pots, so, I actually prefer trimmed bowls aesthetically, which (when i am throwing without a specific project in mind) I throw on the hump most of the time anyway. What other tricks are there to eliminate trimming?

dPancioli;
I remember that when I was first learning to throw, the prof would have us check the thickness of a cylinder with a needle tool. Should be about one quarter of an inch. As I became a better thrower, I realized that the real weight was hiding in that corner where the bottom moves into the wall. The weight is eliminated if you make a conscious effort to undercut the wall at the base on the inside of the piece.[Don't know if this makes sense, it's easier to demonstrate]. Cylinders don't really require trimming. You should practice getting that clay up into the wall of the pot. All of us have to trim at some point.
TJR.

I teach a lot of new throwers, so I will answer my own question about heavy bottoms.

When the pot is heavy, I suggest that they cut the bottom off and roll it (the bottom) to proper thinness. Then with a knifepare out the extra clay on the inside of the piece (usually the bottom 1 inch).

Then, if they choose, at this point they can alter the form, for example, oval it, or make aleaf shape of it (a pointed oval) or a triangle ,etc. Then put the form back on the bottom, cut the bottom to shape, scratch and attach.

This tends to give the pot a "front and back" or "two fronts" to surface.I think it is good for students to discover that thrown pots can be reshaped and thatdesigning on a "flatter" surface rather than totally round, can also lend something to the form.

I was trained with the needle tool trick but I still tend to get my bottoms too thin, I have to watch it. May be I could put the thumb tack in the middle and just leave it there until I finish throwing. Denice